Tm-fiber laser pumped Ho:YAG MOPA system delivering 534 W average output power at a pulse repetition frequency of 10 kHz

Through a four-stage amplifier configuration, the maximum average output power of Ho:YAG MOPA system reached 534 W at a pulse repetition frequency of 10 kHz and a pulse width of 52.5 ns, corresponding to the pulse energy of 53.5 mJ and a peak power of 1.017 MW. To the best of our knowledge, this is the maximum average output power for the 2 μm pulsed laser system.

Additionally, a polarization-purified laser was obtained by inserting a thin-film polarizer in each amplifier to filter out the depolarized laser. The maximum average output power of the polarization-purified laser was 432 W, and the beam quality M² factors were measured to be 1.93 and 1.51 in the x and y directions,respectively.